Duffy's 1/71 Series 1 240z build

[nomuken]

On 5/2/2019 at 11:32 PM, duffymahoney said:

I screwed something up in the trans rebuild, it becomes tight with the front cover on, plus I guess I love spending money, so I decided on the KA swap for my 240z.  This is a longer tail shaft on the trans, so it should fit in my series 1 better (no cutting), plus the 1st is better gear ratio and 2nd is slightly better.  I found a 1989 240sx trans, with 576 miles on it.  It's been in storage inside since 12/01/89!  Zinc is still in tact.  Paid too much for it, but hopefully it's good.  The shop tested all the gears and syncros.  

Digging up this older post. I have a series 1 to, still stock 4 speed. Do you have to cut the trans tunnel at all with the SX gearbox? I don't want to cut it and the idea of a 90§ bent shifter isn't appealing to me. So a SX 5spd swap might be the solution...

[duffymahoney]

5 hours ago, nomuken said:

Digging up this older post. I have a series 1 to, still stock 4 speed. Do you have to cut the trans tunnel at all with the SX gearbox? I don't want to cut it and the idea of a 90§ bent shifter isn't appealing to me. So a SX 5spd swap might be the solution...

Zero cutting with the sx swap. 

[duffymahoney]

Well I’m probably a idiot. But I decided to swap my Jenvey throttles bodies out for something a little more vintage/ classic. 

These are late 70s early 80s SK throttle bodies. They are 47mm that taper to 45. I picked them up off yahoo japan. They have a nice vac balance port on them. I bought two sets off a single seller. 

Now time to fabricate a single piece fuel rail and find a tps sensor that works. They should match my SK intake nicely. The old SK stuff is so nicely cast. I’m excited!

[grannyknot]

Were there any problems with the Jenvey TBs that helped you make the switch? 

[duffymahoney]

My 3.1ish stroker build ran into a small issue. The block will need to be clearanced a little more. The extra long stroked LD crank (84.6) is to blame. 

The engine can be rotated, and it just barely touches about one time out of three. That’s just the .002” of bearing clearance rocking one way or another.

Deck height is within .002” of each other. 

Andrew Kazanis is a L series wizard. Hopefully when he retires he will build Datsun motors and especially do more head work.

[wheee!]

Easy fix...

[conedodger]

On 9/7/2019 at 7:21 AM, duffymahoney said:

So getting a vac log/ map signal has proved very hard with my manifold.  

 

 

 

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So I am going to attempt to re tap my BSPT threads to NPT (I have had great success with it actually) Then use these.

 

 

 

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https://www.universalpowerconversion.com/miniature-male-branch-tee-hose-barb-brass-p-3356.html

 

https://www.universalpowerconversion.com/miniature-male-branch-tee-hose-barb-brass-p-3368.html

 

So the runners will all have a 1/8 NPT by 1/8 Hose barb T.  That way I can connect to a map sensor and also the FPR.  

 

Then on the runner with 1/4 NPT, I will use the 1/4 NPT by 1/8 hose barb T, then tap (or soldier) the top flat section to 1/8 NPT by 3/8 Hose barb (3/8 will go to the brake booster).  Then I have nice braided vacuum hoses to make the balance tube/ vac log.  Should look good and solve all my issues.  

Duffy,

I had a similar problem getting a vacuum signal I could use on a Porsche I own. All those throttle plates opening at once creates a heck of an atmospheric drop. I ended up using a mig tip to mitigate the vacuum drop. It wasn't heavenly, but it made it more tuneable.

For reference, this is what a MIG welding tip looks like. It's simply an obstruction with a small hole in to modulate changes in vacuum, and anything could be used (aluminum rod with a drilled hole, a carb jet, a drilled plastic BB, etc). In a way, it introduces a 'lag' or slowdown of changes in vacuum, so you get a sort of averaging effect. Much better than having the MAP sensor report every peak and valley in the signal, and having the FI trying to keep up with that.
 

[conedodger]

Another thought @duffymahoney. What about using MAF instead of MAP? Or TPS? 

[duffymahoney]

Maf doesn’t work with ITB. If i used a intake box it would. 
 

I will use tps for most load tables. 
 

 

 

[conedodger]

I just assumed you were going to use one of those carbon fiber airboxes with a MAF like mine that will give you IAT and such. But TPS works...

Edited September 13, 2020 by conedodger

[duffymahoney]

No. I plan on some sort of stack filters. 
 

Maybe someday something like this 

[AK260]

No. I plan on some sort of stack filters. 
 
Maybe someday something like this 

Those beautiful and expensive DCOEs are being suffocated with that airbox. Even with my SUs on a modified engine, I can see the defects of / proven that the airbox is very restrictive.

What@conedodger put up is the way forward IMHO. Combine that with some piping through the rad panel and a filter in front of the rad pulling in cold air and you should see a few more ponies too!